Avis falls 8% on weaker European demand

A passenger boards an Avis shuttle bus at Los Angeles International Airport.

Shares of Avis Budget Group fell more than 8 percent amid a volume spike, following comments made Tuesday about weaker European demand in August.

Hertz Global Holdings shares were also down nearly 6 percent in sympathy with its car rental rival, trading at its lowest level since July, according to Factset.

Avis Budget Group President and CFO David Wyshner spoke during a Deutsche Bank conference presentation Tuesday, and said that August's European demand was "disappointing." Wyshner noted that although Avis' European revenue increased year-over-year, "inbound demand was soft all along the Mediterranean, negatively impacting pricing in France, Italy and Spain."

Wyshner added that the weaker demand in Europe negatively affected peak pricing across the industry for the month of August, and was not exclusive to Avis brands.

"My sense is that this softness was driven more by security concerns than by the Brexit vote or the Olympics or the broader economy, but all four probably played a role," he said. "The silver lining would be that in-country rental volumes were okay, and the rest of the year in Europe is more dependent on commercial business than on leisure travelers, so we would not expect the impact in future months to be at all like what we saw in August."

When asked for comment, Avis directed CNBC to its conference presentation. Hertz did not immediately respond to CNBC's request for comment.